Wednesday, March 25, 2015


I mentioned this animal in class when we were discussing photosynthesis.

This beautiful green leafy organism is actually a sea slug. The sea slug Elysia chlorotica consumes chloroplasts when it eats the algae Vaucheria litorea. The slug feeds on the algae, but the chloroplasts are retained in the cells of the gut. The gut in this sea slug is highly branched and the chloroplasts give it the green color. The chloroplasts in the tissue of the animal's gut continue to function in the animals without an algal cell being present. The slug lives about 10 months and can survive off the food made by the chloroplasts.

The green color also provides great camouflage. While the animal has to eat an algae to get the chloroplasts, it is intriguing that the chloroplasts can continue to function without any algal cells present as genes in the nucleus of the algae are needed for photosynthesis to occur. So where are the genes to support photosynthesis? In the nucleus of the sea slug cells! The slug gets the genes from the algae, it does not have them until the animal feeds on the algae.

Interested in looking into this gene transfer further? Click here to read a paper by Mary E. Rumpho et al. on horizontal gene transfer between the algae and the slug.

Photosynthesis from Space

When the chloroplasts in the leaves of plants absorb sunlight, some of the light is released from the leaves in a phenomenon called fluorescence. The light that is released is too dim for our eyes to see it, but it can be seen from satellites in space. Take a look. Click here to watch a short video of this fluorescence

Wednesday, March 4, 2015

Bio 120 review for Exam 2

DNA and Genetic Engineering Review Questions



1. Describe the structure of the DNA molecule




2. If the sequence of bases on one stand of the molecule is AAC TGC CCG, what is the sequence on the complementary strand?




3. During DNA replication, what enzyme breaks the hydrogen bonds between the base pairs, and what enzyme matches up nucleotides to the existing ones on the parent strand of DNA?





4. Why is this type of replication called Semi Conservative?






5. How is RNA different from DNA?






6. The production of messenger RNA from DNA is called ________, and this happens in the __________ of the cell.






7. mRNA gets a cap and a tail prior to being read by the ribosome. What is the function of the cap and tail?






8. If the DNA strand being copied had this sequence: ACT GGC ATA CTA what would the sequence of the mRNA be?



9. The function of transfer RNA is ?




10. What is the name of the enzyme that produces RNA from DNA?






11. If the sequence of DNA is the same in your body cells, why are all cells not the same?








12. The DNA in you, an earthworm, and a fungus is the same. So why are you a human and not an earthworm?








13. What is an anti-codon and where is it found?








14. The protein synthesis process that occurs at the ribosome is called _____________








15. What is a stop codon, and what happens when one is read in the ribosome?












Genetic Engineering  


1. What are restriction enzymes?






2. What kind of cells have restriction enzymes, and what is the purpose of these enzymes in the cell?






3. What is a plasmid?






4. How are plasmids used in genetic engineering?






5. Why does human DNA work in a bacterial cell?






6. What is gene therapy?






7. How are small fragments of DNA separated during the DNA fingerprinting process?






8. What benefits are there to inserting a human gene into a bacterium? What possible problems could arise from genetically engineered organisms being released into the wild?








Mitosis and Meiosis Review

1. If a cell has 8 chromosomes and does mitosis, how many cells will be made, and how many chromosomes will each cell have?





2. If a cell has 8 chromosomes and does meiosis to make sperm cells, how many cells will be made, and how many chromosomes will each cell have?





3. Mitosis creates cells which are ________, while meiosis makes cells which are _____.




4. What are homologous chromosomes?





5. What are sister chromatids?





6. What is crossing over, and during which process, (mitosis or meiosis) does it occur?





7. Why is crossing over important?





8. During __________ of mitosis sister chromatids separate.





9. During _________ of meiosis homologous pairs of chromosomes separate, but during ____________ of meiosis sister chromatids separate.





10. In meiosis, typically four sperm cells are made, but meiosis only makes one large egg cell. Why?




Plant Diversity





1. Which of the following is found in gymnosperms, and which is found in angiosperms?

A. seeds
B. pollen
C. Vessel cells in xylem
D. tracheid cells in xylem



2. What is the function of the anther in the flower?



3. Which of the following is where one would find ovules?

A. in an anther
B. in the ovary
C. in the stigma
D. in the style



4. Ovules are

A. eggs
B. spores that will become pollen
C. spores that will become eggs
D. immature seeds
E. pollen grains



5. In double fertilization the first sperm fertilizes the egg and the second

A. dies
B. is only used if the first sperm cell dies
C. fertilizes another egg
D. fertilizes a haploid endosperm mother cell to make diploid endosperm
E. fertilizes a diploid ( n+n) endosperm mother cell to make triploid endosperm



6. What is the function of fruit?



7. Microspores become
A. the embryo sac
B. the mature male gametophyte
C. pollen grains
D. eggs
E. only B and C above



8. What is the oldest plant on Earth, and what is the most massive


9. How are confiers adapted to life in cold dry climates?



10. What is missing in moss that is present in ferns?
A. swimming sperm
B. seeds
C. pollen
D. vascular tissue
E. ovules



11. Why are flowering plants so much more diverse than the gymnosperms?



12. What do ferns and mosses share in common?
A. seeds
B. swimming sperm
C. pollen
D. vascular tissue
E. dominant sporophyte generation



13. During a plant's life cycle the _______ generation is diploid and makes spores
A. sporophyte
B. gametophyte
C. sori
D. sporangia
E. photosynthetic







Fungi  
1. A lichen is made of a ____ and a ____. What is the ecological role of lichens?
2. What role do fungi play typically in their habitat?
3. How are fungi different from plants?
4. How do fungi feed?
5. How do fungi spread out in their habitat?
6. The body of a fungus is a thread like structure called a ____
6. A mass of the answer in question 6 is call a ____


Tuesday, February 24, 2015

Botany 120 Review for exam 2

Movement of  Water in the plant.
1. Describe the path a water molecule would take to enter the root, move into the xylem and up the stem of a plant and out a stoma in the leaf.
2. How is xylem different from phloem?
3. What forces are involved in the movement of water up a plant?
4. What determines if stomata are open or closed?

Plant Anatomy:
1. Pick one of the ground tissues we discussed such as parenchyma or sclerenchyma, and explain how its structure and function are related.
2. What are the two types of vascular tissue in plants, and what is the function of each?
3. How is the anatomy of a monocot root, or stem or leaf different from that of a dicot?
4. What is the role of the epidermis? In woody plants the epidermis is replaced by the _______ ?
5.What are the regions called in plants where mitosis occurs to make the plant taller?
6. What is the name of the openings in the epidermis and what is the function of these openings?
7. In a dicot leaf, why is the lower layer of mesophyll more open than the upper layer?
8. What part of the root actually absorbs the water?
9. What is the difference between spring and summer wood?
10. How are compound and simple leaves different?
11. What is the function of the following stem modifications: tuber, bulb, corm, rhizome, stolon, tendril
12. What are five modifications of stems or leaves that might be found in a plant adapted to hot dry conditions?
13. Why are some plant's leaves modified to trap insects?
14. What is the role of the endodermis in the root?
15. What is the function of the pericycle?

DNA
1. Describe the structure of the DNA molecule
2. If the sequence of bases on one stand of the molecule is AAC TGC CCG, what is the sequence on the complementary strand?
3. During DNA replication, what enzyme breaks the hydrogen bonds between the base pairs, and what enzyme matches up nucleotides to the existing ones on the parent strand of DNA?
4. Why is this type of replication called Semi Conservative?
5. How is RNA different from DNA?
6. The production of messenger RNA from DNA is called ________, and this happens in the __________ of the cell.
7. If the DNA strand being copied had this sequence: ACT GGC ATA CTA what would the sequence of the mRNA be?
8. The function of transfer RNA is ?
9. What is the name of the enzyme that produces RNA from DNA?
10. What is an anti-codon and where is it found?
11. The protein synthesis process that occurs at the ribosome is called _____________
12. What is a stop codon?

Mitosis and Meiosis
1. If a cell has 8 chromosomes and does mitosis, how many cells will be made, and how many chromosomes will each cell have?
2. Mitosis creates cells which are ________.
3. What are sister chromatids?
4. When mitosis is over, how does a plant cell divide up the cytoplasm?
5. Describe what happens in anaphase.
6. What are spindle fibers?
7. How can you tell a plant cell is in prophase?
8. During what part of the cell cycle is DNA replicated?
9. If a plant cell with a diploid number of 12 does meiosis the cells produced will have ___ chromosomes
10. What are homologous chromosomes?
11. What is crossing over and why is it important?
12. How is metaphase 1 in meiosis different from metaphase 1 in mitosis?


Wednesday, February 4, 2015

Bio 120 Review for First Exam Chapters 1-3 and 13

Biology 120 
Here are some review questions for you. Some may be similar to the daily review questions, but all will help you while you prepare for the exam.

Chapters 1 and 2
1. How is a hypothesis different from a theory?

2.What are five characteristics of living things?

3. What is a hydrogen bond, and why are these bonds important to life?

4. Oxygen has 8 electrons, with 6 in the outermost energy level. Will this atom react?

5. How are ions formed?

6. A solution with a pH of 5 is how many times more acidic than a solution with a pH of 7?

7. What determines if an atom with react with another?

8. How are polar and non polar covalent bonds different?

9. How is the polar nature of water related to:
a. its high boiling point
b. surface tension
c. the solid form being less dense than the liquid form

10. What is an acid? What is a base?


Organic Molecules
1. What are the building blocks of carbohydrates?

2. What is the difference between a saturated and unsaturated fatty acid?

3. Why is the shape of an enzyme important to the function of the enzyme?

4. At what level of complexity do proteins usually become functional?

5. What makes up a nucleotide?

6. What bond forms between amino acids as they react to form proteins?

7. How is the function of carbohydrates different in plants and animals?

8. Which of the macromolecules we discussed stores energy in the most efficient way?

9. What is the most common steroid in the body?

Chapter 3
1. How are the mitochondria and chloroplasts similar?

2. Why do we think mitochondria and chloroplasts were once independent organisms?

3. Describe the plasma membrane. Include how a lipid membrane functions in a watery environment.

4. What role do the proteins in the plasma membrane play?

5. How are prokaryotic cells different from eukaryotics cells?

6.What can cyanobacteria do that the bacteria living in your mouth do not do?

7. What are the functions of the Golgi bodies?

8.Describe briefly what organelles would be involved in making a protein and exporting it from the cell.

9.Give an example of two cell organelles working together to accomplish a task.

10.What organelle is found on the ER?

11.What is the function of lysosomes?

12.Where is the nucleolus, and what is its function?


Osmosis and Diffusion

1. A plant cell in a hypertonic solution will under go _____________

2. An animal cell in a hypotonic solution may undergo _____________

3. A cell must maintain an imbalance of sodium ions on either side of the membrane for it to function.
 What process would it most likely use of the ones we discussed in class?

4. How is active transport different from diffusion and osmosis?

5. How is dialysis different from osmosis?

6. What affect would a hypertonic solution have on a cell?

7. In a hypotonic solution water would move ________ a cell.

8. If a .9% salt solution is isotonic to a red blood cell, a 2% salt solution would be _____.



Microbes
1. How are viruses different from other microbes covered in class?

2. How do viruses get into cells?

3. Eukaryotic cells reproduce using mitosis, how do prokaryotic cells reproduce?

4. What are the three common shapes of bacteria, and why is shape important?

5. How are the protists different from bacteria?

6. What is a capsule in bacterial cells?

7. How are the Archaeans different from Bacteria?

8. How do Paramecium, Amoeba, and Euglena move and feed?

Monday, February 2, 2015

Measles- One of the most contagious viral diseases

In Bio 120 we recently talked about viruses, how they enter cells and once their how they take over the cells to make copies of the virus. Click on the link below to learn more about measles, how it spreads and what it does to your body. In light of the outbreak here in Southern CA, it would be wise for you to be sure you have been vaccinated. Measles article